AI started using the Woodland Bakery SMBC frosting. It has been a big hit the first 2 times I made it. The butter I used was unsalted land o lakes. I ran out & went to our local HEB grocery store & bought the store brand unsalted butter. Made a 3 rd batch for a different cake with the store brand butter & it tasted like spoonfuls of butter! The smbc tasted completely different..... I weigh all my ingredients so I know I didn't measure incorrectly.... Does the butter brand really make a difference???

ALook at the ingredients listing on the box and compare between the two butters you used. That may give you an answer., maybe? But then "natural flavoring" as an ingredient can vary widely from one brand to another......my answer to you would be yes. The store brand had much more "natural flavoring" than the LOL does. I don't know what it is, but the flavoring they use seems to concentrate on itself in buttercream.